001 /*
002 * Copyright (c) 2007-2014 Concurrent, Inc. All Rights Reserved.
003 *
004 * Project and contact information: http://www.cascading.org/
005 *
006 * This file is part of the Cascading project.
007 *
008 * Licensed under the Apache License, Version 2.0 (the "License");
009 * you may not use this file except in compliance with the License.
010 * You may obtain a copy of the License at
011 *
012 * http://www.apache.org/licenses/LICENSE-2.0
013 *
014 * Unless required by applicable law or agreed to in writing, software
015 * distributed under the License is distributed on an "AS IS" BASIS,
016 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
017 * See the License for the specific language governing permissions and
018 * limitations under the License.
019 */
020
021 package cascading.tap.hadoop;
022
023 import java.beans.ConstructorProperties;
024 import java.io.IOException;
025
026 import cascading.scheme.Scheme;
027 import cascading.tap.SinkMode;
028 import cascading.tap.TapException;
029 import cascading.tuple.Fields;
030 import org.apache.hadoop.fs.FileSystem;
031 import org.apache.hadoop.mapred.JobConf;
032
033 /**
034 * Class Lfs is a {@link cascading.tap.Tap} class that provides access to the Local File System via Hadoop.
035 * <p/>
036 * Note that using a Lfs {@link cascading.tap.Tap} instance in a {@link cascading.flow.Flow} will force a portion of not the whole Flow to be executed
037 * in "local" mode forcing the Flow to execute in the current JVM. Mixing with {@link cascading.tap.hadoop.Dfs} and other Tap
038 * types is possible, providing a means to implement complex file/data management functions.
039 * <p/>
040 * Use {@link cascading.tap.hadoop.Hfs} if you need a Tap instance that inherits the default {@link FileSystem} used by Hadoop.
041 */
042 public class Lfs extends Hfs
043 {
044 @ConstructorProperties({"scheme"})
045 Lfs( Scheme scheme )
046 {
047 super( scheme );
048 }
049
050 /**
051 * Constructor Lfs creates a new Lfs instance.
052 *
053 * @param fields of type Fields
054 * @param stringPath of type String
055 */
056 @ConstructorProperties({"fields", "stringPath"})
057 @Deprecated
058 public Lfs( Fields fields, String stringPath )
059 {
060 super( fields, stringPath );
061 }
062
063 /**
064 * Constructor Lfs creates a new Lfs instance.
065 *
066 * @param scheme of type Scheme
067 * @param stringPath of type String
068 */
069 @ConstructorProperties({"scheme", "stringPath"})
070 public Lfs( Scheme scheme, String stringPath )
071 {
072 super( scheme, stringPath );
073 }
074
075 /**
076 * Constructor Lfs creates a new Lfs instance.
077 *
078 * @param scheme of type Scheme
079 * @param stringPath of type String
080 * @param replace of type boolean
081 */
082 @ConstructorProperties({"scheme", "stringPath", "replace"})
083 @Deprecated
084 public Lfs( Scheme scheme, String stringPath, boolean replace )
085 {
086 super( scheme, stringPath, replace );
087 }
088
089 /**
090 * Constructor Lfs creates a new Lfs instance.
091 *
092 * @param fields of type Fields
093 * @param stringPath of type String
094 * @param sinkMode of type SinkMode
095 */
096 @ConstructorProperties({"fields", "stringPath", "sinkMode"})
097 @Deprecated
098 public Lfs( Fields fields, String stringPath, SinkMode sinkMode )
099 {
100 super( fields, stringPath, sinkMode );
101 }
102
103 /**
104 * Constructor Lfs creates a new Lfs instance.
105 *
106 * @param scheme of type Scheme
107 * @param stringPath of type String
108 * @param sinkMode of type SinkMode
109 */
110 @ConstructorProperties({"scheme", "stringPath", "sinkMode"})
111 public Lfs( Scheme scheme, String stringPath, SinkMode sinkMode )
112 {
113 super( scheme, stringPath, sinkMode );
114 }
115
116 protected void setStringPath( String stringPath )
117 {
118 if( stringPath.matches( ".*://.*" ) && !stringPath.startsWith( "file://" ) )
119 throw new IllegalArgumentException( "uri must use the file scheme" );
120
121 super.setStringPath( stringPath );
122 }
123
124 protected FileSystem getFileSystem( JobConf conf )
125 {
126 try
127 {
128 return FileSystem.getLocal( conf );
129 }
130 catch( IOException exception )
131 {
132 throw new TapException( "unable to get handle to get local filesystem", exception );
133 }
134 }
135 }